Why this sudden panic over milk from cloned cows? Or, rather, from their offspring.

We report, along with The Daily Mail and The Guardian, that a British farmer has been selling milk from cows which were born to cloned parents. It's illegal, so maybe it's worth a note somewhere in the middle of the paper, but the Mail put it on their front page, while we've been running it on the homepage of our website all morning, as have The Guardian. What is it that is getting people so exercised?

Presumably – although none of the reports quite comes out and says this, or refutes it – it's because people are scared that milk from these animals will, in some way, be toxic.

Now. How likely is this? In short, not very. A cloned animal should be genetically identical to the parent, excepting mutation, unless it has been genetically modified.

Now, it is possible, I suppose, that a mutation could mean that the cow would make different milk. But this would be equally possible in a cow born in the usual way, or via artificial insemination. Cloning probably does cause more mutations on average than usual sexual reproduction – Dolly the Sheep died young, suffering from arthritis and lung problems, and it is believed that this may have been a result of the cloning.

But any mutation is not enough. A mutation that would make the milk unsafe would have to be very specific; it would have to create a toxin in milk, in sufficiently large quantities to be dangerous, but which was flavourless and odourless so that it wouldn't affect the milk. The animal itself would have to survive having this toxin within it, and – since these are the offspring of a cloned animal we're talking about – if it nursed its own children, they would have to survive it too, without significant ill-effects. It would have to be something that could be created via biochemical pathways, as well – unless the mutation creates a fusion-powered cow, they're not going to be creating heavy metals or arsenic in their udders. The odds against are staggering.

According to one geneticist I spoke to, "the chances would roughly be the same as that of your mother developing toxic milk while breastfeeding you as an infant.

"Nasties in a cow's diet may well end up in the milk, but that's a matter of what the farmer feeds them, not whether or not they are cloned."

I want to stress at this stage that I'm not an expert, and my hasty rush around to find one in time to get quotes in time for this blog was not a total success: the above is from someone who specialises in nematode worms, and they wanted to remain anonymous because this isn't their area. But nonetheless, I stand by my statement that the odds of cloned milk being a health risk are negligible. Laughable, even.

That's not to say there aren't real reasons to have a serious ethical debate over cloning. As Dolly's case demonstrates, the animals may suffer from genetic problems: my geneticist contact tells me that a process called "DNA demethylation" which takes place during ordinary reproduction does not occur in cloning, which can mean that some genes which should be active are turned off. We need to be aware that cloning could create animals which suffer more than most – although, frankly, given the conditions many farm animals are kept in as it is, it doesn't seem like people care all that much about that. (Which is strange, given how heated they get about laboratory animals. But that's a discussion for elsewhere.)

But that's nothing to do with human health. The scare-story aspect of this seems to be nothing more than a generalised fear of the unknown; it's Not Natural, as though "natural" is synonymous with "good". It's the same as our fear of "chemicals" (as though everything isn't a chemical) in our food, the same as our nervousness about "playing God" – a charge which gets levelled at Craig Venter every couple of months. There's no reason to worry about this. Unless my guess about the nuclear-powered cows is accurate, obviously; that would be terrifying.